1. Field of the Invention
The present invention relates to a light-emitting diode (hereinafter, referred to as LED) configured to mount a light-emitting element on a substrate provided with electrodes.
2. Description of the Related Art
A conventional LED includes a light-emitting element mounted on a substrate provided with a pair of electrodes, and the light-emitting element is electrically connected to the pair of electrodes on the substrate through bumps, wires, and/or mounting the light-emitting element at its one of a pair of element-electrodes disposed on one of the pair of electrodes of the substrate. (see, for reference, Japanese Unexamined Patent Application Publication Nos. 2005-353802 and 2003-23183).
FIGS. 9 and 10 illustrate a structure from the aforementioned conventional LEDs. An LED 1 includes a substrate 2, a pair of upper electrodes 3a and 3b formed on an upper surface of the substrate 2 by etching a metallic film formed on the upper surface of the substrate, a light-emitting element 4 disposed on one 3a of the pair of upper electrodes and connected to another 3b of the pair of upper electrodes through a bonding wire 5, and a light-transmitting member 6 provided on the upper surface of the substrate 2 to seal the light-emitting element 4 and electrical connecting portions to the light-emitting element 4.
Each of the upper electrodes 3a and 3b are electrically connected to each of a pair of lower electrodes 3a and 3b provided on a lower surface of the substrate 2 by a through-hole penetrating from the upper surface and the lower surface of the substrate. The light-transmitting member 6 is formed on the upper surface of the substrate to seal the light-emitting element 4, the bonding wire 5, and the pair of upper electrodes 3a and 3b. 
The substrate 2 includes a glass cloth 7 as a core material and a resin material 8 such as glass epoxy-based resin, BT resin, or the like covering the glass cloth 7, as shown in FIG. 11A. Because the resin material 8 in general deteriorates by light radiation and/or heat, and if deterioration of the resin material 8 in the substrate 2 proceeds, the resin material 8 may be discolored as shown in FIG. 11B and a layer of the resin material 8 may be peeled off as shown in FIG. 11C, and that affects the product quality of LED.
Since an upper surface of the substrate 2 except portions where the pair of upper electrodes 3a and 3b are provided is exposed to light emission from the light-emitting element 4, the upper surface of the substrate of such an LED 1 as shown in FIGS. 9 and 10, for example, is affected by light radiation as mentioned above
In addition, if the exposed upper surface of the substrate has a large area, the exposed area absorbs and wastes light emitted from the light-emitting element. Accordingly, light absorbed in the exposed area of the substrate not only deteriorates the substrate but also wastes light emission of the light-emitting element.